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(ModeL) A. RIX.

BALL GASTER. No. 372,387. Patented Nov. 1, 1887.

NlTED STATES PATENT rice.

ALFRED RlX, OF SAN FRANCISCO, CALIFORNIA.

BALL-CASTER.

SPECIFICATION forming part of Letters Patent No. 372,387, dated November1, 188?.

Application filed November 30, 1886. Serial X0. 220,32. (ModeL) To allwhom, it may concern.-

Be it known that I, ALFRED RIX, of the city and county of San Franciscoand State of California, have made an Improvement in Ball-Casters, ofwhich the following is a specification.

The object of the invention is a caster having its point of support uponthe floor directly beneath the leg supported, and at the same timemovable in any direction with no hitch and but little friction.

It consists of a ball within a socket considerably larger than the ball,with the space between filled not quite full of small balls, like shot,which I call pellets, loosely disposed in a single layer or bed, andacting as rollers,

and kept in place by a stop at the lower edge of the socket.

The accompanying drawing is an enlarged vertical central section view,(substantially,) and constitutes a part hereof.

A is the ball; 13, the upper part of the socket; O, the lower part; I),the pellets; E, the stop, and E a modification of the same. This stop isplaced high enough to clear the floor and low enough to allow areturn-channel for the pellets not under pressure. The drawing shows agood example. The stop is so made and placed that the point at which thepellets come in contact with it shall be near enough to the ball toprevent the pellets from wedging between the stop and the ball. Thedrawing shows two kinds-cach properly constructed-so as to allow thepellets to rest and move upon it without wedging, the one at E havingits upper face a trough with a curve a little greater than that of thepellets, and the one at E with its face plain and in line with thecenter of the ball.

As to the absolute size of the pellets, they should not be so small asto drop out on little wear, and as to their size relatively to the ballthey should not be so large as to clog in the returnrhannel or preventthe ball from protruding sufficiently.

Pellets one-eighth of an inch in diameter work well with a ball one inchand a quarter in diameter. The fit of the pellets between the ball andsocket should not be tight nor very loose, but fairly free, so that whenthe upper part of the socket rests upon the pellets the lower partof thesocket will fall away from the ball slightly. The action will not provesatisfactory if the pellet-chamberis full. The amount of vacancy for thebest action is about one-tenth of the chamber. A few tests for anyparticular construction will determine how much the vacancy should be.This vacancy, when the caster is in action, is more or less distributedamong'thc pellets under pressure, whereby their rubbing againstcaehother is almost wholly prevented. The socket is shown divided at thecenter, with the lower part spun upon the upper. This allows the upperpart to be conveniently formed and finished, and the lower part to bemade together with the stop; but the socket can be a single piece andthe stop spun or otherwise fastened to it.

A convenient way of filling the pellctchanr her when the socket isdivided at the center, as shown, is to turn the upper part of the socketupside down and arrange a few pellets in a single layer at the (then)bottom with the ball upon them. Then place over them a form preciselylike the lower part of the socket with the stop omitted. Finally, filland remove the form and put on the lower part of the socket.

The operation is obvious. All the pellets not under pressure between theupper hemispheres go to the lower part of the chamber, where they restupon the stop and are free to be moved. As the caster moves forward inany direction the rear pellets roll on the ball upward, over, anddownward in front and drive the loose ones backward through the lowerpart of the chamber--the return-cha11- nel-a part turning to the rightand a part to the left. This backward movement is also aided by theaction of the ball. As the ball always presses to the rear, it does notrub against the pellets resting on the stop in front, and as the pelletsunder pressure run substantially clear of each other the action isalmost wholly the rolling one.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is I In and constituting a ball-caster, thecombination of the following parts, to wit: the 1), each partconstructed and all united in the ball A, the socket B, being enoughmore than manner and for the purposes substantially as a hemisphere toaffordthe return-channel deset forth.

scribed, the stop E, presenting its upper side ALFRED RIX. 5 to thepellets, as described, so as to avoid Witnesses:

wedging, and the chamber formed by the ball, WV. W. WATSON,

socket, and stop not quite filled with pellets M. T. MOPHERSON.

